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At least 307 records · Page 17Linked to original sources
PubMed1996

Epithelial-myoepithelial carcinoma of the parotid gland. An unusual cause of ear canal stenosis.

Epithelial-myoepithelial carcinoma (EMC) accounts for approximately one per cent of salivary gland tumours. This tumour is gaining wider recognition following inclusion into the WHO histological classification of salivary gland tumours in 1990. Salivary gland tumours characteristically present with an enlarging mass. We describe an unusual presentation of a salivary gland tumour with stenosis of the external ear canal in the absence of a palpable mass. EMC usually arises from the salivary glands but isolated cases have been described arising primarily from the paranasal sinuses, trachea and lacrimal gland. The management of this tumour is still evolving with surgical excision being the main-stay of treatment. The efficacy of radiotherapy has not yet been established but high local recurrence rates despite apparently adequate excision and the possibility of a multicentric origin of the tumour may herald an increasing role for radiotherapy in the future. We stress the importance of awareness of adjacent structures when considering the cause of cartilaginous canal stenosis.

Carcinoma↗
PubMed1996

Misdiagnosis of hearing loss due to ear canal collapse: a report of two cases.

Collapse of the external auditory meatus during audiometry can lead to spuriously increased hearing thresholds being obtained, particularly at high frequencies, and may simulate conditions such as noise-induced hearing loss, presbyacusis and retrocochlear pathology. Consequently, inappropriate investigations and management may be undertaken. Two patients with elevated thresholds secondary to ear canal collapse are described. The implications of initially failing to identify the true nature of their 'hearing losses' are highlighted and strategies to avoid such pitfalls are discussed.

Adult↗
PubMed1983

Estimation of the area function of human ear canals by sound pressure measurements.

A method to determine the "area function" of a duct, i.e., the variation of the cross section along the middle axis of the duct is described. It is shown that it is sufficient to measure the sound pressure at three locations in the duct to get knowledge of the area function. The calculated approximation fits the true area function the better the broader the bandwidth of the sound pressure signals is chosen. The bandwidth is bounded by the condition that no higher modes of sound propagation must be excited. In principle, the area function can be determined by solving a linear system of equations and executing a simple iterative algorithm. Some more work however is necessary to stabilize the computation against unavoidable small measuring errors. The calculated area function reproduces the acoustical transformation characteristics with good precision. In spite of this the calculated area function may disagree with the real area function in some regions, especially at the edges. Such errors occur, if the deviations of the area function from constant cross section correspond to frequencies outside the range of measurement. The method was applied to determine the area function of human ear canals and the results are presented.

Ear Canal↗
PubMed1997

Composition of lipids from the glands of the external ear canal of the adult chicken.

Six classes of neutral lipids, i.e. triacylglycerol (TG), free fatty acids (FFA), monoester waxes (MW), free- and esterified sterols (FST and SE), and squalene (SQ) were identified by thin layer chromatography of the lipid materials extracted separately from the secretion as well as from the isolated whole glands present in the skin of the floor of the external ear canal of the domestic fowl. Secretory lipids contained considerable proportions of MW fractions (17.03%), TG (22.23%), and SQ (14.66%), while TG was the major component (41.10%) in the lipids from the isolated glands. Polar lipids, which comprised about 16-20% of total glandular lipids, were shown to be composed primarily of sphingomyelin.

Animals↗
PubMed2002

Occurrence of Malassezia spp. in the external ear canals of dogs and cats with and without otitis externa.

We studied the lipophilic microbiota of the external ear canals of 332 animals (264 dogs and 68 cats), with and without otitis externa, over an 11-year period from 1988 to 1999. Malassezia pachydermatis was isolated from 62.2% and 50% of dogs with and without otitis externa, respectively, and from 41.2% and 17.6% of cats with and without otitis externa, respectively. In the group of animals studied for lipid-dependent species, these yeasts were isolated from 4.5% of dogs with otitis externa and from 23.1% and 8.9% of cats with and without otitis externa, respectively. M. sympodialis and M. furfur were isolated from cats and M. furfur and M. obtusa from dogs. Our findings show that lipid-dependent Malassezia species may contribute to the etiology of otitis externa in dogs and cats.

Animals↗
PubMed2002

Spectral shapes of forward and reverse transfer functions between ear canal and cochlea estimated using DPOAE input/output functions.

It is widely assumed that the distortion characteristics of the cochlea are uniform across its length, or at least across some portion of its length. For each distortion product otoacoustic emission (DPOAE) input/output (I/O) function across frequency, there is a corresponding cochlear I/O function defined over the cochlear source region. An assumption of distortion invariance is adopted such that these cochlear I/O functions are identical across tonotopic place, which is testable in the sense that a single nonlinear function should adequately describe the set of DPOAE I/O functions across frequency. If so, the differences in measured DPOAE I/O functions across frequency are produced by differences in the forward stimulus transmission to the generation site, and reverse DP transmission back to the ear canal. The absolute transfer-function magnitude is not determined by this technique, but the spectral shapes across frequency and between ears are determined. The role of middle-ear functioning is implicit in the I/O functions because of its controlling influence on these transfer functions. Results have been obtained using the average DPOAE I/O functions measured in a population of healthy ears [Gorga et al., J. Acoust. Soc. Am. 107, 2128-2135 (2000)], and support the hypothesis of cochlear-distortion invariance. The measured forward and reverse transfer functions have a general bandpass characteristic, and a more narrow-band structure with similarities to the behavioral threshold curve.

Auditory Perception↗
PubMed2001

Factors affecting the frequency of ear canal and face infestation by Otodectes cynotis in the cat.

Otodectes cynotis is responsible for at least 50% of canker cases diagnosed in cats world-wide. The role of Demodex cati in the pathogenesis of otitis and acne is still obscure. The aims of this study were to estimate the prevalence of O. cynoyis and D. cati infestations in clinically normal cats in northern Greece, to determine the factors that are associated with the probability and severity of infestation in the cat, and to examine the importance of these mites in the pathogenesis of feline acne. Samples from 161 cats were examined by flushing the ear canals and by taking skin scrapings of the chin and lip area. The results were combined with various factors (sex, age, living style, hair coat type and presence of pruritus, of ear discharge, of acne-like lesions) in order to carry out a risk analysis. Two separate logistic regression analyses were performed. One, on the infestation/non-infestation potential with O. cynotis and the other, on the degree of such infestation as mild-to-moderate (< or =5 mites/field) or severe (>5 mites/field). D. cati was not detected in any of the 161 cats. The prevalence of O. cynotis was estimated at 25.5% (95% confidence interval (CI) 19-32). The rate of mite infestation was higher with the presence of ear discharge (odds ratio 9, 95% CI 3.3-24.5), periaural pruritus (odds ratio 3.6, 95% CI 1.8-8) and acne-like lesions (odds ratio 3.3, 95% CI 1.2-9). Cats with mild-to-moderate degree of infestation had 18 times higher chance of exhibiting an ear discharge than those with a severe infestation. The log-odds of mild-to-moderate parasitism were linearly related to the age.

Acne Vulgaris↗
PubMed2005

Malassezia pachydermatis isolated from normal and diseased external ear canals in dogs: a comparative analysis.

To investigate the role of Malassezia pachydermatis as a pathogenic agent in canine otitis, a comparative analysis of isolates from normal and diseased external ear canals in dogs was undertaken. Specimens were collected from the ears of dogs with unilateral or bilateral otitis and from healthy dogs. Mycological analysis was by direct microscopy and fungal culture on Sabouraud's dextrose agar and Dixon's agar. Of the otitis specimens, 63.7% showed typical Malassezia cells on cytological examination. In samples taken from the healthy ears of dogs with unilateral otitis, only 21.43% (P<0.05) showed evidence of Malassezia. M. pachydermatis was identified cytologically and culturally in 57.53% (P<0.05), 14.29% and 30.0% of samples from the ears of dogs with otitis, from the healthy ears of dogs with unilateral otitis and from the ears of healthy dogs with no otitis. In the group with otitis associated with M. pachydermatis, the poodle was the most common breed (39.29%; P<0.05), whereas in the group without otitis, the German Shepherd breed was prominent (although this observation was not statistically significant). In both groups, the majority of dogs with M. pachydermatis were aged between 1 and 3 years (P<0.05). The higher incidence of M. pachydermatis isolated from the ears of dogs with otitis externa suggests a putative pathogenic role of this yeast in this condition.

Animals↗